Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/lib/kobject.c
Parent Directory | Revision Log
Revision 630 -
(show annotations)
(download)
Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 11321 byte(s)
Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 11321 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * kobject.c - library routines for handling generic kernel objects |
3 | * |
4 | * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org> |
5 | * |
6 | * This file is released under the GPLv2. |
7 | * |
8 | * |
9 | * Please see the file Documentation/kobject.txt for critical information |
10 | * about using the kobject interface. |
11 | */ |
12 | |
13 | #include <linux/kobject.h> |
14 | #include <linux/string.h> |
15 | #include <linux/module.h> |
16 | #include <linux/stat.h> |
17 | |
18 | /** |
19 | * populate_dir - populate directory with attributes. |
20 | * @kobj: object we're working on. |
21 | * |
22 | * Most subsystems have a set of default attributes that |
23 | * are associated with an object that registers with them. |
24 | * This is a helper called during object registration that |
25 | * loops through the default attributes of the subsystem |
26 | * and creates attributes files for them in sysfs. |
27 | * |
28 | */ |
29 | |
30 | static int populate_dir(struct kobject * kobj) |
31 | { |
32 | struct kobj_type * t = get_ktype(kobj); |
33 | struct attribute * attr; |
34 | int error = 0; |
35 | int i; |
36 | |
37 | if (t && t->default_attrs) { |
38 | for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) { |
39 | if ((error = sysfs_create_file(kobj,attr))) |
40 | break; |
41 | } |
42 | } |
43 | return error; |
44 | } |
45 | |
46 | static int create_dir(struct kobject * kobj) |
47 | { |
48 | int error = 0; |
49 | if (kobject_name(kobj)) { |
50 | error = sysfs_create_dir(kobj); |
51 | if (!error) { |
52 | if ((error = populate_dir(kobj))) |
53 | sysfs_remove_dir(kobj); |
54 | } |
55 | } |
56 | return error; |
57 | } |
58 | |
59 | static inline struct kobject * to_kobj(struct list_head * entry) |
60 | { |
61 | return container_of(entry,struct kobject,entry); |
62 | } |
63 | |
64 | static int get_kobj_path_length(struct kobject *kobj) |
65 | { |
66 | int length = 1; |
67 | struct kobject * parent = kobj; |
68 | |
69 | /* walk up the ancestors until we hit the one pointing to the |
70 | * root. |
71 | * Add 1 to strlen for leading '/' of each level. |
72 | */ |
73 | do { |
74 | length += strlen(kobject_name(parent)) + 1; |
75 | parent = parent->parent; |
76 | } while (parent); |
77 | return length; |
78 | } |
79 | |
80 | static void fill_kobj_path(struct kobject *kobj, char *path, int length) |
81 | { |
82 | struct kobject * parent; |
83 | |
84 | --length; |
85 | for (parent = kobj; parent; parent = parent->parent) { |
86 | int cur = strlen(kobject_name(parent)); |
87 | /* back up enough to print this name with '/' */ |
88 | length -= cur; |
89 | strncpy (path + length, kobject_name(parent), cur); |
90 | *(path + --length) = '/'; |
91 | } |
92 | |
93 | pr_debug("%s: path = '%s'\n",__FUNCTION__,path); |
94 | } |
95 | |
96 | /** |
97 | * kobject_get_path - generate and return the path associated with a given kobj |
98 | * and kset pair. The result must be freed by the caller with kfree(). |
99 | * |
100 | * @kobj: kobject in question, with which to build the path |
101 | * @gfp_mask: the allocation type used to allocate the path |
102 | */ |
103 | char *kobject_get_path(struct kobject *kobj, int gfp_mask) |
104 | { |
105 | char *path; |
106 | int len; |
107 | |
108 | len = get_kobj_path_length(kobj); |
109 | path = kmalloc(len, gfp_mask); |
110 | if (!path) |
111 | return NULL; |
112 | memset(path, 0x00, len); |
113 | fill_kobj_path(kobj, path, len); |
114 | |
115 | return path; |
116 | } |
117 | |
118 | /** |
119 | * kobject_init - initialize object. |
120 | * @kobj: object in question. |
121 | */ |
122 | void kobject_init(struct kobject * kobj) |
123 | { |
124 | kref_init(&kobj->kref); |
125 | INIT_LIST_HEAD(&kobj->entry); |
126 | kobj->kset = kset_get(kobj->kset); |
127 | } |
128 | |
129 | |
130 | /** |
131 | * unlink - remove kobject from kset list. |
132 | * @kobj: kobject. |
133 | * |
134 | * Remove the kobject from the kset list and decrement |
135 | * its parent's refcount. |
136 | * This is separated out, so we can use it in both |
137 | * kobject_del() and kobject_add() on error. |
138 | */ |
139 | |
140 | static void unlink(struct kobject * kobj) |
141 | { |
142 | if (kobj->kset) { |
143 | spin_lock(&kobj->kset->list_lock); |
144 | list_del_init(&kobj->entry); |
145 | spin_unlock(&kobj->kset->list_lock); |
146 | } |
147 | kobject_put(kobj); |
148 | } |
149 | |
150 | /** |
151 | * kobject_add - add an object to the hierarchy. |
152 | * @kobj: object. |
153 | */ |
154 | |
155 | int kobject_add(struct kobject * kobj) |
156 | { |
157 | int error = 0; |
158 | struct kobject * parent; |
159 | |
160 | if (!(kobj = kobject_get(kobj))) |
161 | return -ENOENT; |
162 | if (!kobj->k_name) |
163 | kobj->k_name = kobj->name; |
164 | parent = kobject_get(kobj->parent); |
165 | |
166 | pr_debug("kobject %s: registering. parent: %s, set: %s\n", |
167 | kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>", |
168 | kobj->kset ? kobj->kset->kobj.name : "<NULL>" ); |
169 | |
170 | if (kobj->kset) { |
171 | spin_lock(&kobj->kset->list_lock); |
172 | |
173 | if (!parent) |
174 | parent = kobject_get(&kobj->kset->kobj); |
175 | |
176 | list_add_tail(&kobj->entry,&kobj->kset->list); |
177 | spin_unlock(&kobj->kset->list_lock); |
178 | } |
179 | kobj->parent = parent; |
180 | |
181 | error = create_dir(kobj); |
182 | if (error) { |
183 | /* unlink does the kobject_put() for us */ |
184 | unlink(kobj); |
185 | if (parent) |
186 | kobject_put(parent); |
187 | } |
188 | |
189 | return error; |
190 | } |
191 | |
192 | |
193 | /** |
194 | * kobject_register - initialize and add an object. |
195 | * @kobj: object in question. |
196 | */ |
197 | |
198 | int kobject_register(struct kobject * kobj) |
199 | { |
200 | int error = 0; |
201 | if (kobj) { |
202 | kobject_init(kobj); |
203 | error = kobject_add(kobj); |
204 | if (error) { |
205 | printk("kobject_register failed for %s (%d)\n", |
206 | kobject_name(kobj),error); |
207 | dump_stack(); |
208 | } else |
209 | kobject_hotplug(kobj, KOBJ_ADD); |
210 | } else |
211 | error = -EINVAL; |
212 | return error; |
213 | } |
214 | |
215 | |
216 | /** |
217 | * kobject_set_name - Set the name of an object |
218 | * @kobj: object. |
219 | * @fmt: format string used to build the name |
220 | * |
221 | * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated |
222 | * string that @kobj->k_name points to. Otherwise, use the static |
223 | * @kobj->name array. |
224 | */ |
225 | int kobject_set_name(struct kobject * kobj, const char * fmt, ...) |
226 | { |
227 | int error = 0; |
228 | int limit = KOBJ_NAME_LEN; |
229 | int need; |
230 | va_list args; |
231 | char * name; |
232 | |
233 | /* |
234 | * First, try the static array |
235 | */ |
236 | va_start(args,fmt); |
237 | need = vsnprintf(kobj->name,limit,fmt,args); |
238 | va_end(args); |
239 | if (need < limit) |
240 | name = kobj->name; |
241 | else { |
242 | /* |
243 | * Need more space? Allocate it and try again |
244 | */ |
245 | limit = need + 1; |
246 | name = kmalloc(limit,GFP_KERNEL); |
247 | if (!name) { |
248 | error = -ENOMEM; |
249 | goto Done; |
250 | } |
251 | va_start(args,fmt); |
252 | need = vsnprintf(name,limit,fmt,args); |
253 | va_end(args); |
254 | |
255 | /* Still? Give up. */ |
256 | if (need >= limit) { |
257 | kfree(name); |
258 | error = -EFAULT; |
259 | goto Done; |
260 | } |
261 | } |
262 | |
263 | /* Free the old name, if necessary. */ |
264 | if (kobj->k_name && kobj->k_name != kobj->name) |
265 | kfree(kobj->k_name); |
266 | |
267 | /* Now, set the new name */ |
268 | kobj->k_name = name; |
269 | Done: |
270 | return error; |
271 | } |
272 | |
273 | EXPORT_SYMBOL(kobject_set_name); |
274 | |
275 | |
276 | /** |
277 | * kobject_rename - change the name of an object |
278 | * @kobj: object in question. |
279 | * @new_name: object's new name |
280 | */ |
281 | |
282 | int kobject_rename(struct kobject * kobj, char *new_name) |
283 | { |
284 | int error = 0; |
285 | |
286 | kobj = kobject_get(kobj); |
287 | if (!kobj) |
288 | return -EINVAL; |
289 | error = sysfs_rename_dir(kobj, new_name); |
290 | kobject_put(kobj); |
291 | |
292 | return error; |
293 | } |
294 | |
295 | /** |
296 | * kobject_del - unlink kobject from hierarchy. |
297 | * @kobj: object. |
298 | */ |
299 | |
300 | void kobject_del(struct kobject * kobj) |
301 | { |
302 | sysfs_remove_dir(kobj); |
303 | unlink(kobj); |
304 | } |
305 | |
306 | /** |
307 | * kobject_unregister - remove object from hierarchy and decrement refcount. |
308 | * @kobj: object going away. |
309 | */ |
310 | |
311 | void kobject_unregister(struct kobject * kobj) |
312 | { |
313 | pr_debug("kobject %s: unregistering\n",kobject_name(kobj)); |
314 | kobject_hotplug(kobj, KOBJ_REMOVE); |
315 | kobject_del(kobj); |
316 | kobject_put(kobj); |
317 | } |
318 | |
319 | /** |
320 | * kobject_get - increment refcount for object. |
321 | * @kobj: object. |
322 | */ |
323 | |
324 | struct kobject * kobject_get(struct kobject * kobj) |
325 | { |
326 | if (kobj) |
327 | kref_get(&kobj->kref); |
328 | return kobj; |
329 | } |
330 | |
331 | /** |
332 | * kobject_cleanup - free kobject resources. |
333 | * @kobj: object. |
334 | */ |
335 | |
336 | void kobject_cleanup(struct kobject * kobj) |
337 | { |
338 | struct kobj_type * t = get_ktype(kobj); |
339 | struct kset * s = kobj->kset; |
340 | struct kobject * parent = kobj->parent; |
341 | |
342 | pr_debug("kobject %s: cleaning up\n",kobject_name(kobj)); |
343 | if (kobj->k_name != kobj->name) |
344 | kfree(kobj->k_name); |
345 | kobj->k_name = NULL; |
346 | if (t && t->release) |
347 | t->release(kobj); |
348 | if (s) |
349 | kset_put(s); |
350 | if (parent) |
351 | kobject_put(parent); |
352 | } |
353 | |
354 | static void kobject_release(struct kref *kref) |
355 | { |
356 | kobject_cleanup(container_of(kref, struct kobject, kref)); |
357 | } |
358 | |
359 | /** |
360 | * kobject_put - decrement refcount for object. |
361 | * @kobj: object. |
362 | * |
363 | * Decrement the refcount, and if 0, call kobject_cleanup(). |
364 | */ |
365 | void kobject_put(struct kobject * kobj) |
366 | { |
367 | if (kobj) |
368 | kref_put(&kobj->kref, kobject_release); |
369 | } |
370 | |
371 | |
372 | /** |
373 | * kset_init - initialize a kset for use |
374 | * @k: kset |
375 | */ |
376 | |
377 | void kset_init(struct kset * k) |
378 | { |
379 | kobject_init(&k->kobj); |
380 | INIT_LIST_HEAD(&k->list); |
381 | spin_lock_init(&k->list_lock); |
382 | } |
383 | |
384 | |
385 | /** |
386 | * kset_add - add a kset object to the hierarchy. |
387 | * @k: kset. |
388 | * |
389 | * Simply, this adds the kset's embedded kobject to the |
390 | * hierarchy. |
391 | * We also try to make sure that the kset's embedded kobject |
392 | * has a parent before it is added. We only care if the embedded |
393 | * kobject is not part of a kset itself, since kobject_add() |
394 | * assigns a parent in that case. |
395 | * If that is the case, and the kset has a controlling subsystem, |
396 | * then we set the kset's parent to be said subsystem. |
397 | */ |
398 | |
399 | int kset_add(struct kset * k) |
400 | { |
401 | if (!k->kobj.parent && !k->kobj.kset && k->subsys) |
402 | k->kobj.parent = &k->subsys->kset.kobj; |
403 | |
404 | return kobject_add(&k->kobj); |
405 | } |
406 | |
407 | |
408 | /** |
409 | * kset_register - initialize and add a kset. |
410 | * @k: kset. |
411 | */ |
412 | |
413 | int kset_register(struct kset * k) |
414 | { |
415 | kset_init(k); |
416 | return kset_add(k); |
417 | } |
418 | |
419 | |
420 | /** |
421 | * kset_unregister - remove a kset. |
422 | * @k: kset. |
423 | */ |
424 | |
425 | void kset_unregister(struct kset * k) |
426 | { |
427 | kobject_unregister(&k->kobj); |
428 | } |
429 | |
430 | |
431 | /** |
432 | * kset_find_obj - search for object in kset. |
433 | * @kset: kset we're looking in. |
434 | * @name: object's name. |
435 | * |
436 | * Lock kset via @kset->subsys, and iterate over @kset->list, |
437 | * looking for a matching kobject. If matching object is found |
438 | * take a reference and return the object. |
439 | */ |
440 | |
441 | struct kobject * kset_find_obj(struct kset * kset, const char * name) |
442 | { |
443 | struct list_head * entry; |
444 | struct kobject * ret = NULL; |
445 | |
446 | spin_lock(&kset->list_lock); |
447 | list_for_each(entry,&kset->list) { |
448 | struct kobject * k = to_kobj(entry); |
449 | if (kobject_name(k) && !strcmp(kobject_name(k),name)) { |
450 | ret = kobject_get(k); |
451 | break; |
452 | } |
453 | } |
454 | spin_unlock(&kset->list_lock); |
455 | return ret; |
456 | } |
457 | |
458 | |
459 | void subsystem_init(struct subsystem * s) |
460 | { |
461 | init_rwsem(&s->rwsem); |
462 | kset_init(&s->kset); |
463 | } |
464 | |
465 | /** |
466 | * subsystem_register - register a subsystem. |
467 | * @s: the subsystem we're registering. |
468 | * |
469 | * Once we register the subsystem, we want to make sure that |
470 | * the kset points back to this subsystem for correct usage of |
471 | * the rwsem. |
472 | */ |
473 | |
474 | int subsystem_register(struct subsystem * s) |
475 | { |
476 | int error; |
477 | |
478 | subsystem_init(s); |
479 | pr_debug("subsystem %s: registering\n",s->kset.kobj.name); |
480 | |
481 | if (!(error = kset_add(&s->kset))) { |
482 | if (!s->kset.subsys) |
483 | s->kset.subsys = s; |
484 | } |
485 | return error; |
486 | } |
487 | |
488 | void subsystem_unregister(struct subsystem * s) |
489 | { |
490 | pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name); |
491 | kset_unregister(&s->kset); |
492 | } |
493 | |
494 | |
495 | /** |
496 | * subsystem_create_file - export sysfs attribute file. |
497 | * @s: subsystem. |
498 | * @a: subsystem attribute descriptor. |
499 | */ |
500 | |
501 | int subsys_create_file(struct subsystem * s, struct subsys_attribute * a) |
502 | { |
503 | int error = 0; |
504 | if (subsys_get(s)) { |
505 | error = sysfs_create_file(&s->kset.kobj,&a->attr); |
506 | subsys_put(s); |
507 | } |
508 | return error; |
509 | } |
510 | |
511 | |
512 | /** |
513 | * subsystem_remove_file - remove sysfs attribute file. |
514 | * @s: subsystem. |
515 | * @a: attribute desciptor. |
516 | */ |
517 | |
518 | void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a) |
519 | { |
520 | if (subsys_get(s)) { |
521 | sysfs_remove_file(&s->kset.kobj,&a->attr); |
522 | subsys_put(s); |
523 | } |
524 | } |
525 | |
526 | EXPORT_SYMBOL(kobject_init); |
527 | EXPORT_SYMBOL(kobject_register); |
528 | EXPORT_SYMBOL(kobject_unregister); |
529 | EXPORT_SYMBOL(kobject_get); |
530 | EXPORT_SYMBOL(kobject_put); |
531 | EXPORT_SYMBOL(kobject_add); |
532 | EXPORT_SYMBOL(kobject_del); |
533 | |
534 | EXPORT_SYMBOL(kset_register); |
535 | EXPORT_SYMBOL(kset_unregister); |
536 | EXPORT_SYMBOL(kset_find_obj); |
537 | |
538 | EXPORT_SYMBOL(subsystem_init); |
539 | EXPORT_SYMBOL(subsystem_register); |
540 | EXPORT_SYMBOL(subsystem_unregister); |
541 | EXPORT_SYMBOL(subsys_create_file); |
542 | EXPORT_SYMBOL(subsys_remove_file); |